This invention relates to pharmaceutical compositions containing 2-acetoxy-5-(α-cyclopropylcarbonyl-2-fluorobenzyl)-4,5,6,7-tetrahydrothieno[3,2-c]pyridine (Prasugrel) or a pharmaceutically acceptable salt thereof, and aspirin, as active ingredients [particularly pharmaceutical compositions for prevention or treatment (particularly for treatment) of diseases caused by thrombus or embolus]; to the use of 2-acetoxy-5-(α-cyclopropylcarbonyl-2-fluorobenzyl)-4,5,6,7-tetrahydrothieno[3,2-c]pyridine or a pharmaceutically acceptable salt thereof and aspirin for the manufacture of pharmaceutical compositions for prevention or treatment (particularly for treatment) of diseases caused by thrombus or embolus; and to methods for the prevention or treatment (particularly to methods for the treatment) of diseases caused by thrombus or embolus by administration of an effective amount of 2-acetoxy-5-(α-cyclopropylcarbonyl-2-fluorobenzyl)-4,5,6,7-tetrahydrothieno[3,2-c]pyridine or a pharmaceutically acceptable salt thereof and aspirin to warm-blooded animals (particularly humans).
2-Acetoxy-5-(α-cyclopropylcarbonyl-2-fluorobenzyl)-4,5,6,7-tetrahydrothieno[3,2-c]pyridine has been described in the Japanese Patent Application Publication No. Hei 6-41139, and possesses potent inhibitory activity against platelet aggregation. Furthermore, aspirin is well known to have an inhibiting activity against platelet aggregation, although the activity is low. However, pharmaceutical compositions containing both compounds have not been known.